1. Field of the Invention
The present invention relates to a double-chuck mechanical pencil provided with a front chuck for gripping a lead, and a back chuck provided with a chuck ring loosely put thereon to project a lead by a fixed length and, more particularly, to a double-chuck mechanical pencil provided with an eraser support structure in its back portion.
2. Prior Art
There have been proposed various double-chuck mechanical pencils incorporating improvements to reduce waste leads. In the double-chuck mechanical pencil of this kind, if either the front or the back chuck is turned by some cause while a lead is gripped by both the front and the back chuck, the lead is twisted and broken. Fragments of the broken lead remaining in a space between the front and the back chuck obstruct a lead projecting operation, and a front portion and a back portion of the broken lead are dislocated relative to each other in projecting the broken lead to make the projection of the broken lead impossible.
If the user turns a push cap or an eraser holder connected through a lead tank to the back chuck inadvertently or the back chuck is turned together with the lead tank when an eraser is used, a lead gripped by both the front and the back chuck is twisted and broken.